package org.bouncycastle.asn1;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class BERGenerator extends ASN1Generator {
    private boolean _tagged = false;
    private boolean _isExplicit;
    private int _tagNo;

    protected BERGenerator(OutputStream out) {
        super(out);
    }

    public BERGenerator(OutputStream out, int tagNo, boolean isExplicit) {
        super(out);

        _tagged = true;
        _isExplicit = isExplicit;
        _tagNo = tagNo;
    }

    public OutputStream getRawOutputStream() {
        return _out;
    }

    private void writeHdr(int tag) throws IOException {
        _out.write(tag);
        _out.write(0x80);
    }

    protected void writeBERHeader(int tag) throws IOException {
        if (_tagged) {
            int tagNum = _tagNo | DERTags.TAGGED;

            if (_isExplicit) {
                writeHdr(tagNum | DERTags.CONSTRUCTED);
                writeHdr(tag);
            } else {
                if ((tag & DERTags.CONSTRUCTED) != 0) {
                    writeHdr(tagNum | DERTags.CONSTRUCTED);
                } else {
                    writeHdr(tagNum);
                }
            }
        } else {
            writeHdr(tag);
        }
    }

    protected void writeBERBody(InputStream contentStream) throws IOException {
        int ch;

        while ((ch = contentStream.read()) >= 0) {
            _out.write(ch);
        }
    }

    protected void writeBEREnd() throws IOException {
        _out.write(0x00);
        _out.write(0x00);

        if (_tagged && _isExplicit) // write extra end for tag header
        {
            _out.write(0x00);
            _out.write(0x00);
        }
    }
}
